Question: What is matter?
Answer: Any substance that has mass and occupies space.
Question: What is matter made up of?
Answer: Matter is made up of very small particles.
Question: What makes liquids take the shape of the container they are poured in?
Answer: Liquids take the shape of the container they are poured in because the particles are not as tightly packed as in solids.
Question: List any three processes to show that matter changes from one state to another.
Answer: The three processes to show that matter changes from one state to another are :-
Question: How does heating and cooling affect the movement of particles?
Answer: On cooling the movement of particles decreases
On heating the movement of particles increases.
Question: Explain in what way is the arrangement of particles related to the states of matter.
Answer: All matter is made up of every small particles. The arrangement of particles results in three states of matter:-
- Solids: In solids the particles are very closely packed and because of this mostly solids have fixed shape.
- Liquids: In liquids particles are not as closely packed as in solids. This is the reason liquids can take the shape of the container they are poured into.
- Gases: In gases particles are very loosely packed and they can easily flow from one place to another.
Question: Describe how the states of matter change in terms of the movements of tiny particles.
Answer: In terms of the movement of particles the changes in states of matter will be as follow:
- Melting: In this process a solid changes into a liquid on heating. The particles of the solid will start changes moving faster on heating and break away from their rigid pattern thus making a liquid.
- Freezing: In this process a liquid changes into a solid on cooling. When the liquid is cooled the movement of its particles will decrease and they will pack themselves into a rigid shape thus forming a solid.
- Evaporation: In this process a liquid changes into a gas on heating. The particles start moving faster on heating and break free from their existing pattern thus making a gas.
- Condensation: In this process a gas changes into a liquid on cooling. Cooling of the gas will decrease the movement of its particles making them free to move thus forming a liquid.
Question: Explain the processes of contraction and expansion.
Answer: The processes of contraction and expansion
- In this process the size of the matter increases.
- When the substance is heated the particles start moving rapidly
- Because of the increased movement of particles they take up more space and thus expand.
- In this process the size of the matter decreases.
- When the substance is cooled the movement of particles slows down.
- Because of the decreased movement of particles they take up less space and thus contract.
Question: Describe an example to show that substances expand on heating and contract on cooling.
Answer: Due to expansion and contraction the electric cables appear to hang loosely from the poles during summer but do not appear loose in winter.
Question: Differentiate between solids, gases and liquids.
Question: Name some liquids which evaporates easily.
Answer: Liquids which evaporates easily are :-
Alcohol, kerosene, petrol, water and nail paint remover alcohol.
Question: Rita want’s to get ready for party but her dress is wet. Suggest some ways by which she can dry her dress.
Answer: Ways by which she can dry her dress are :-
- If it is morning time she can let her dress dry under the sun.
- She can iron the dress.
- She can dry the dress using a hair dryer.
Question: Why do clothes dry faster in summers than in winters.
Answer: Due to the heat of sun and the temperature is high in summers that is why clothes dry faster in summers than in winters.
Question: Why do chocolates melt on heating?
Answer: Chocolates melt on heating because when the particles are heated they break the rigid pattern and start moving faster thus taking space than before.